Indicators for the direction of travel, referred to as direction indicators, are required for applications in vehicles. A direction indicator has the function of using a lighting means to indicate to other road users if the road user wishes to change the direction of travel. Direction indicators have been implemented electromechanically, efforts being made to replace these electromechanical solutions by more economical electronic ones. A contemporary direction indicator is composed of a direction indicator circuit, a direction indicator switch and a plurality of lighting means, for example incandescent lamps. Since an electronic solution is intended to replace an established electromechanical solution, value is placed on a direction indicator circuit which is as economical as possible and on an overall solution which is an economical as possible. The direction indictor circuit, the direction indictor switch and the lighting means are connected in series between the supply voltage and the vehicle ground or a ground terminal of the vehicle. If the direction indicator switch is closed, the lighting means is to flash with a defined frequency, that is to say light up or not light up periodically. The frequency is defined as 1.5 Hz or 3 Hz, wherein the frequency of 3 Hz indicates a fault in a lighting means.
Direction indictor circuits in vehicles are used in environments which are very demanding in terms of the robustness and the reliability of the direction indictor circuit and the direction indicator per se. Direction indicators are subject to low and high temperatures, a high degree of humidity, to soiling and dirt of all types and to electromagnetic emissions. For an electronic circuit it is advantageous if, on the one hand, it is robust with respect to these stresses and, on the other hand, does not generate any stresses for other circuits. If an electronic circuit generates such stress, for example as a result of generating a large amount of heat or, for example, due to high electromagnetic emissions, then a high level of expenditure has to be made during operation to minimize this stress again at a different design level. A circuit which only has low electromagnetic emission has a high cost advantage for the user since the user can, for example, dispense with expensive filters. A further cost advantage can be achieved in that components are generally replaced by more cost-effective and robust components. At present, capacitors which are larger than 200 μF are used to supply direction indicator circuits. If the power consumption of the direction indictor circuit is reduced, a smaller and therefore more cost-effective capacitor can be used.